454/th400/np203 1970 k10 swb fleet

[BIGRAGU]

Hello guys,
I have recently purchased a 1970 Chevy SWB Fleetside. It has a 350 smallblock,TH350, and somebody has swapped in an NP208 out of an 80's Blazer. My plan is to drop in a 454 RAT and a TH400 and get rid of that ugly np208 and find a 203 for it like I think it would have came with. Has anyone out here done this combo in a pickup like this before? I am wondering if there are any unforseen problems that I am going to run into. I understand that I will need to get the right output shaft for the th400, for 4x4, and the correct adapter plate to go in between the th400 and the np203. I am also assuming that I will have to have some work done on the driveshafts. If anyone out there has any thoughts I would appreciate them. Thanks, Chris
P.S. If there is anyone within a couple of hundred miles of Brainerd MN that have any of these components for sale let me know.

[1969k10stepside]

Search the 4wd section for info on a big block swap in a 4wd.It can be done but will require work.The 70-72 4wds had the NP205 t-case stock.If it was me,I'd look for one of them before swapping in a 203.

[BIGRAGU]

Hey 1967k10stepside,
Thanks for setting me straight on the T-case. I previously,15 years ago, owned 4 of these pickups. Back then I was pretty up to speed on them, man the things a person forgets! For the past several years I have owned GM Duramax pickups. They have been very good vehicles but I miss my old 1969-70 models so the Duramax is for sale. Does anyone know of a site that will lay out what equipment was available in a given model year such as transmission, T-case, diffs and so on? Once again thanks for the help.

[1969k10stepside]

Don't know of a site but have owned a few of these too.I know from experience this much about that sorta stuff in the truck series.
Transmissions for 4wds:
1967-SM420 4spd
1968-1972 SM465 4spd
1970-1972 TH350
1967-1972 3spd Manual
Transfer Cases
1967-1969 Rockwell T221
1970-1972 NP205
Axles 1/2 and 3/4 ton:
1967-1970 Dana 44 closed knuckle w/ drum brakes
1970-Open Knuckle w/ Drum brakes
1971-1972 Open Knuckle w/ Discs
On the rear..1/2 ton:
12 Bolt Corp.
3/4 ton:
Eaton HO52-Mostly in Chevys
Dana 60-Mostly in GMCs

[special-K]

Originally Posted by BIGRAGU

Does anyone know of a site that will lay out what equipment was available in a given model year such as transmission, T-case, diffs and so on? Once again thanks for the help.

Yeah,this one.Just ask and you`ll get your answer.For what you`re wanting to do you should try asking in the 4wd forum.Alot of guys are wanting BBCs in these 4wds.Other than just to say they have a big block,I don`t know why.I,personally,don`t think it`s worth the trouble unless you have an extra one laying around.I`ve never had a lack of power from a SBC and the 383 I had built for my old CheyenneSuper had all the torque of a big block.The K-models are darn snug to the firewall already and with an HEI even worse.A BBC will require damaging the firewall to get clearance.I call it "damaging" because someone else may not like to see this done to a cab when looking to buy.It`s getting harder to find a good cab and this will be just another deterent like a cut dash,etc.
I`m not telling anyone what to do with their truck.Just food for thought.I like to find trucks that previous owners haven`t "damaged" for their personal likes and many feel the same way.Think about 15 years from now.I used to want to do this.But,after some thought have decided I`ll keep my big blocks in my 2wds if I want one.

[72armyswbtruck]

Definitely a much better transfer case the np 205 over the np 203

[mrein3]

I stored a 72 for a kid a couple of winters ago. It had a th400 and NP205. Obviously swapped from a newer vehicle as the 67-72s never had this combo. However I posted this fact to let you know that it is doable. Anything is doable for that matter.

What I would do if I was you is look for a th400/np205 combo (rare) but I wouldn't be afraid of a 205/th350 combo behind a 454 that isn't too wild.

special-K speaks highly of his 383 and I would have to agree. I have the same engine in my truck and love it. Not to mention that I put it together for right around $1200. About HALF what a 454 would cost to put together.

IF your truck had stock components in it, swapping a stock tranny/adapter/t-case with another stock tranny/adapter/t-case takes no crossmember or drive shaft changes. Back then GM used the same components on ALL stock trucks. The difference in the lengths of the drive trains was made up in the adapter between the tranny and t-case.

If you go with the 383 or some other small block engine, I would SERIOUSLY consider a 700r4 with the advanced adapters output shaft that works with the stock NP205. When I swapped in my th350, knowing a 383 was in my future, gas was $1.20 - $1.50 per gallon. I figured gas would have to get up to $3/gallon to make the extra cost of screwing around with a 700r4 worth it. Well, hindsight being 20/20, I sure wish I put the 700 in there because we're all pumping $3/gallon gas now.

Not to mention a 700 pushes your engine almost 2 inches forward of where it sits in front of a stock tranny. This solves some of the things special-K is talking about (like HEI clearance).